Visibly marked motion picture film and method of making same



R. N. TITUS June 7, 1 932.

VISIBLY MARKED MOTION PICTURE FILM AND METHOD OF MAKING SAME Filed March 1. 1929 ZENJQ/U MM I BY W541i Patented June 7, 1932 UNITED STATES PATENT OFFICE ROBERT N. TITUS, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COM- PANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK VISIBLY MARKED MOTION PICTURE FILM AND METHOD OF MAKING SAME Application filed March 1, 1929. Serial No. 343,762.

This invention relates to photography and more particularly to a process for produclng visible images on photographic light sensltive material, such as edge markings on motion picture film. One object of my invention is to provide aprocess for marking photosensitive material which will immediately produce visible marks which will not rub off f or become ofl'set on another convolution of film wound against the marked film. Another objcct is to provide a stable material which may be termed an ink substitute which will not, at ordinary temperatures vaporize thus fogging the photosensitive material. Another object is to provide an ink substitute which is of a consistency to render it readily applicable to-photosensitive material with known apparatus, such as numbering stamps, stencils, etc. Still another object of my invention is to provide an ink substitute or writing fluid which makes a permanent mark on the photosensitive material by the formation of a silver sulphide image therein, such an image being unaffected by subsequent film treatment, and other objects will appear from the following specification, the novel features being particularly pointed out in the claims at the end thereof.

I am aware that photosensitive material such as motion picture film band has been marked in various manners for identification: as for instance by light printing on the film, by'printing with ordinary printing ink and the like. Light printing requires great care to prevent unwanted light from fogging the film and must be developed to be visible;

Ink of the usual type requires time to dry,

, is liable to smear or offset and may be afiected bythe usual fluid film treatment as well as quite possibly affected by the film polishing and cleaning operations when such are required.

My present invention relates to a marking fluid which overcomes the above difiiculties in that the markings are immediately visible, permanent, will not offset and are not affected by any standard film treatment.

I have found that a visible image of high stability may be made on film through chemical action with one of the film constituents leaving an image of silver sulfide grains in the film the desired result can be accomplished.

It should be understood that for best results the sulfiding material must be such that it can be readily applied to the film; that it will not spread from the place applied to the film; and that it is not readily dispersed at room temperature into the atmosphere so as to have a deleterious efl'ect on the photosensitive material.

The desired result may be accomplished with an ink substitute containing a material to cause the formation of a silver sulfide image in the film. Examples of such ink substitutes are:

Emample .I. to 5 g. of sodium sulfide are dissolved in 100 c. c. of water. This solution produces the silver sulfide image instantaneously, and the contrast of the image can be readily controlled as it is a function of the concentration of the sodium sulfide.

Example 2-1/ to 20g. sodium sulfide dissolved in 100 c. c. of water and A; to 10 g. of sodium alginate. This solution is of fairly high viscosity, may be readily applied by suitable means, and produces a sulfide silver image immediately.

Ewample 3. to 20 g. sodium sulfide in a solution of 100 c. c. of water, and to 10% gum tragacarth.

The ink substitutes in the above cited examples may be used in various ways to mark photographically sensitive film, and for marking with any desirable data.

As a typical example of my invention as applied to motion picture film edge markings I have indicated in the accompanying draw- 0 ing diagrammatic views of a marked film and a typical applicating device.

Coming now to the drawing wherein like reference characters denote like parts throughout Fig. 1 is a digrammatic fragmentary plan view of a film marked in accordance with my invention, and

Fig. 2 is a diagrammatic side elevation part in section of a typical printing device for transferring marking fluid to the film.

In Fig. 1, a film 1 may consists of the usual cellulosic base or support coated with a gelatino silver halide emulsion 2. There may be lines 5' and transverse lines 6, which lines of course are not visible on undeveloped film.

It is customary to mark film in long strips. Accordingly a long band is coiled at 10, and the film passes a station 11 where the printing operation occurs, after which the film may be again coiled up as at 12.

The printing station is diagrammatically illustrated as consisting of a tank 13 containing marking fluid 14: which may be of the type above described containing sodium sulfide with or without a viscosity producing material.

This fluid 14: may be transferred by an ab sorbent wheel 15 to a rotary type carrying stam 16 which contacts with the film 1 when the lm is lowered by pressure roll 17 carried by the movable bracket 18.

Bracket 18 also carries guide rolls 19, and, as the film may be threaded between rolls 18 and 19 it may be moved to and from the printing roll with the bracket.

It is customary to mark film with the makers name or symbol as at 25, and possibly footage marks or symbols 26 may be placed every sixteen picture frames if desired. An ordinary type of numbering stamp may be used for this purpose if desired as my mark- .ing fluid may be of the proper viscosity to use with the commercial article.

It is also possible, when required, to furnish marking fluid of low viscosity for use 1n hand marking with ordinary pen as used with ordinary ink.

But whatever the way my marking fluid is applied, it produces, by changing the film coating to silver sulfide, a permanent, visible record which will withstand the usual film treatments.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A method of producing instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with an agent adapted to convert that portion of the emulsion marked to silver sulfide.

2. A method of producing instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with sodium sulfide.

3. A method of producin instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with sodium sulfide and a viscosity producing agent.

4. A method of producing instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with sodium sulfide and sodium alginate.

5. A method of producing instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with a soluble sulfide.

6. A method of producing instantly visible markings on a film coated with a gelatino silver halide emulsion comprising marking said emulsion with a sodium sulfide solution containing sodium alginate.

7. A method of producing instantly visible markings on a filmcoated with a gelatino silver halide emulsion comprising marking said emulsion with a marking fluid made up in accordance with the following formula: to 20 g. sodium sulfide dissolved in 100 c. c. of water and to 10 g. of sodium alginate.

Signed at Rochester, New York, this 25th day of Feb. 1929.

ROBERT N. TITUS. 

